126 lines
3.1 KiB
Go
126 lines
3.1 KiB
Go
package health
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import (
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"encoding/json"
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"net/http"
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"sync"
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)
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var (
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handler = &healthHandler{
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useJSON: false,
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status: Up,
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}
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)
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// responseBody is the body of the response returned by the health handler.
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type responseBody struct {
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Status string `json:"status"`
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Reason string `json:"reason,omitempty"`
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}
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// healthHandler is the HTTP handler for serving the health endpoint
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type healthHandler struct {
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useJSON bool
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status Status
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reason string
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mutex sync.RWMutex
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}
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// WithJSON configures whether the handler should output a response in JSON or in raw text
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//
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// Defaults to false
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func (h *healthHandler) WithJSON(v bool) *healthHandler {
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h.useJSON = v
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return h
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}
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// ServeHTTP serves the HTTP request for the health handler
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func (h *healthHandler) ServeHTTP(writer http.ResponseWriter, _ *http.Request) {
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var statusCode int
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var body []byte
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h.mutex.RLock()
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status, reason, useJSON := h.status, h.reason, h.useJSON
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h.mutex.RUnlock()
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if status == Up {
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statusCode = http.StatusOK
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} else {
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statusCode = http.StatusInternalServerError
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}
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if useJSON {
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// We can safely ignore the error here because we know that both values are strings, therefore are supported encoders.
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body, _ = json.Marshal(responseBody{Status: string(status), Reason: reason})
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writer.Header().Set("Content-Type", "application/json")
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} else {
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if len(reason) == 0 {
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body = []byte(status)
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} else {
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body = []byte(string(status) + ": " + reason)
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}
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}
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writer.WriteHeader(statusCode)
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_, _ = writer.Write(body)
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}
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// Handler retrieves the health handler
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func Handler() *healthHandler {
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return handler
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}
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// GetStatus retrieves the current status returned by the health handler
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func GetStatus() Status {
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handler.mutex.RLock()
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defer handler.mutex.RUnlock()
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return handler.status
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}
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// SetStatus sets the status to be returned by the health handler
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func SetStatus(status Status) {
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handler.mutex.Lock()
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handler.status = status
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handler.mutex.Unlock()
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}
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// GetReason retrieves the current status returned by the health handler
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func GetReason() string {
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handler.mutex.RLock()
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defer handler.mutex.RUnlock()
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return handler.reason
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}
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// SetReason sets a reason for the current status to be returned by the health handler
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func SetReason(reason string) {
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handler.mutex.Lock()
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handler.reason = reason
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handler.mutex.Unlock()
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}
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// SetStatusAndReason sets the status and reason to be returned by the health handler
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func SetStatusAndReason(status Status, reason string) {
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handler.mutex.Lock()
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handler.status = status
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handler.reason = reason
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handler.mutex.Unlock()
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}
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// SetHealthy sets the status to Up and the reason to a blank string
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func SetHealthy() {
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handler.mutex.Lock()
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handler.status = Up
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handler.reason = ""
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handler.mutex.Unlock()
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}
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// SetUnhealthy sets the status to Down and the reason to the string passed as parameter
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//
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// Unlike SetHealthy, this function enforces setting a reason, because it's good practice to give at least a bit
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// of information as to why an application is unhealthy, and this library attempts to promote good practices.
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func SetUnhealthy(reason string) {
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handler.mutex.Lock()
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handler.status = Down
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handler.reason = reason
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handler.mutex.Unlock()
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}
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